Congenital Adrenal Hyperplasia

CAH is the commonest form of adrenal insufficiency with an incidence of approximately 1 in 15,000. The basic defects are genetic defects in the function of several different enzymes, leading to deficient cortisol synthesis and secretion and an over-reaction of excess ACTH which stimulates the production of steroid precursors leading to excess as androgens. Androgen excess can lead to genital virilization and bone age advance. The commonest form is 21-hydroxylase deficiency. The basic challenge is to address the cortisol deficiency with glucocorticoid replacement which will lower ACTH and androgens, without causing cortisol toxicity. This a major clinical challenge.